Structural and functional aspects of chemical carcinogenesis will be investigated by studies of 1) stereochemical effects on DNA alkylation by a bulky activated carcinogenic polycyclic aromatic hydrocarbon (PAH) and the reason that this DNA damage escapes the action or repair enzymes, 2) the roles played by metal ions in biochemical reactions that control the growth and other cellular processes that are affected by cancer and, 3) the types of reactions that free radicals can undergo in a biological setting and the mechanisms that nature uses to modify and control them. Results from these proposed studies will increase out understanding, on a molecular scale, of a wide range of processes involved in cancer, and will help in the design of agents to prevent or combat disease.